Using indicator variables with host input variables

When you associate an indicator variable with an input variable, you must explicitly set the indicator variable, using the values in Table 4-2 as a guide.

**Table 4-2: Indicator variable values used with input variable**
Value	Meaning
-1	Treat the corresponding input as a null value.
0	Assign the value of the host variable to the column.

You must supply host language code to test for a null input value and set the indicator variable to -1. This informs Client-Library of a null value. When you set the indicator variable to -1, null is used regardless of the host variable’s actual value.

The following example demonstrates associating an indicator variable with an input variable. The database royalty column will be set to a null value because R-INDIC is set to -1. Changing the value of R-INDIC changes the value of royalty.

exec sql begin declare section end-exec

 01   R-INDIC   PIC S9(4) COMP.

 01   R-VAR     PIC X(10).

 exec sql end declare section end-exec.

     MOVE -1 TO R-INDIC.

     exec sql update titles

             set royalty = :R-VAR :R-INDIC

         where pub_id="0736" end-exec.